Lift truck with horizontally slewable load carrier

ABSTRACT

A lift truck is provided with a lift mast having a horizontal slewable load carrier. In one aspect of the lift truck the body thereof is provided with an operator&#39;&#39;s cab having a load bearing roof onto which the load carrier can lower its load after being horizontally slewed to a laterally facing position. In another aspect of the lift truck, the fixed and movable upright guides of the lift mast are aligned longitudinally of the lift truck with the load carrier being mounted to the movable guide for vertical movement and for horizontal slewing.

United States Patent McIntyre et al. 1 Aug. 1, 1972 [54] LIFT TRUCK WITH HORIZONTALLY [56] References Cited SLEWABLE LOAD CARRIER UNITED STATES P T TS 72 Inventors: Maurice J. McIntyre, Langley,

\ British Columbia, Canada; John 9 3,323,664 6/1967 Loef et al ..2l4/75 G Newton, Salem, Oreg. Primary Examiner-Gerald M. Forlenza [73] Assrgnee: Skagit Corporation, Sedro Woolley, Assistant Johnson Wash- Attorney-Robert C. Smith and Plante, Hartz, Smith 22 Filed: Nov. 19, 1970 & Thompson [21] Appl. No.: 91,163 [57] ABSTRACT Related US. Application Data A lift truck is provided with a lift mast having a horizontal slewable load carrier. In one aspect of the [63] Commuauon of June lift truck the body thereof is provided with an opera- 1968, abandoned' tors cab having a load bearing roof onto which the load carrier can lower its load after being horizontally [52] US. Cl ..214/75 R, 214/730, 214/672 slewed to a laterally facing position In another aspect [51] Int. Cl. ..B66f 9/14 of the lift truck, the fi d and movable upright guides [58] F eld of Search ..2l4/75, 660, 670-674, f the lift mast are aligned longitudinally f the lift truck with the load carrier being mounted to the movable guide for vertical movement and for horizontal slewing.

6 Claims, 4 Drawing Figures PATENTEDAUB 1 I912 SHEET 1 [1F 4 mm wv \Om m.

iv VN TON A TTORNE YS minnows H912 3.680.721

SHEET 2 OF 4 FlG 2 INVENTORS MAURICE J. MC INTYRE JQHN R. NEWTON t v Q ATTORNEYS PATENTEDAUB I me I 3680.721 SHEEIBOHI INYENTORS MAURICE J. MC INTYRE BY is ATTORNEYS FIG PATENTEDAUB 1 1912 3.680.721

' saw u or 4 INYENTORS MAURICE J. MC INTYRE BY JOHN R. NEWTO ATTORNEYS LIFT TRUCK WITH I-IORIZONTALLY SLEWABLE LOAD CARRIER This application is a continuation of a copending U.S. Pat. application entitled Lift Truck with Horizontally Slewable Load Carrier, Ser. No. 740,707, filed June 27, 1968, now abandoned.

This invention relates to lift trucks. More particularly, this invention relates to lift trucks adapted to handle large, elongated loads such as stacked lumber in restricted areas.

Lift trucks designed to handle large, elongated loads have been proposed wherein a load carrier, such as a fork lift carrier, can be disposed in a forward facing position relative to the truck to pick up a load and then slewed to a laterally facing position to place the elongated load parallel to the truck for transport. These lift truck designs are intended to facilitate transport of elongated material along narrow isles and yet permit front end loading and unloading. However, the load capacity of such lift trucks is often limited, to a maximum weight or width or both, by lift truck structure that cannot withstand the forces imposed by large loads, or that unbalances the truck when the load is slewed to a laterally facing position, or that blocks the operators lateral line of sight when the load is slewed to a laterally facing position.

A primary object of this invention is to provide a lift truck wherein a load carrier is adapted to be horizontally slewed from a forward facing position to a laterally facing position and to overlay the load bearing roof of an operators cab when in the laterally facing position.

Another object is to provide such a lift truckwhereinthe lift mast if fixed and movable guides are mounted by the truck body parallel with the longitudinal axis of the body with the load carrier horizontally slewable relative to the lift mast guides.

These and other objects and advantages of the invention will become apparent from the following description and the accompanying drawings of which:

FIG. 1 is a side elevation view of a preferred embodiment of the invention;

FIG. 2 is a front elevation view of the FIG. 1 embodiment;

FIG. 3 is a plan view in partial cross section taken along the line 3-3 of FIG. 2; and

FIG. 4 is a perspective view of the FIG. 1 embodiment with certain components blown apart in assembly diagram form.

In brief, the lift truck of the present invention comprises a body carried by forward and rearward wheel assemblies and mounting a lift mast. The lift mast includes a first guide fixed against vertical reciprocity movement, a second movable guide mounted by the first guide for vertical reciprocatory movement, a load carrier mounted by the movable guide for vertical reciprocatory movement and adapted to be horizontally slewed, means for vertically raising and lowering the movable guide and the load carrier, and means for horizontally slewing the load carrier.

In one aspect of the invention, the body is provided with an operators cab having a reinforced load bearable roof, and the lift mast is so constructed that when the load carrier is raised to an elevation exceeding that of the body cab, the load carrier and its load can be slewed to overlay the cab. Placing the load over the cab permits more even distribution of the load on the vehicle thereby enabling the transport of heavier and wider loads with a greater degree of stability. In this aspect of the invention, the operators forward line of sight is through the front end framework of the body, and his lateral line of sight to both sides is completely unob structed by the load.

In another aspect of the invention, the fixed and movable guides of the lift mast are mounted parallel with the lift truck longitudinal axis and the load carrier is pivotally mounted to the movable guide such that it is substantially perpendicular to the stationary guide when in its forward facing position and is substantially parallel to the fixed guide when in its laterally facing position. The fixed guide is preferably pivotally mounted for slight pivotal movement on a horizontal axis and means to pivot the fixed guide about such axis are provided to afford tilting adjustment of the load carrier when the latter is in a forward facing position. In this aspect of the invention, the structure of the fixed and movable guides is not mounted for horizontal slewing movement and therefore a massive vertical pivot mechanism is not required to accomplish the required horizontal slewing of the load carrier. This aspect not only reduces the structural requirements of the lift mast but also permits reduction of the size of the lift mast element so that a greater portion of the body width can be effectively utilized to accommodate a loaded laterally facing lift carrier with the load center being maintained adequately close to the longitudinal axis of the vehicle.

Referring to the Figures, a preferred embodiment of the lift truck of this invention is a rear-engine vehicle comprising a body 10, forward and rearward wheel assemblies l2 and 14 on which the body is carried, and a lift mast assembly 16. The body is a low silhouette structure with a height sufficient to accommodate the necessary headroom in an operators cab 18. The roof 20 of the cab is a reinforced structure designed to bear the weight of a load carried by the lift mast assembly. The roof structure comprises a pair of vertical frames, each having a cut out section along their upper sides as shown in FIG. 4, and a plurality of overhead cross bars connected to and extending between the upper sides of vertical frames. As thus structured, the cab roof constitutes a load supporting deck onto which the load carrier can lower its load for transport without continued force exerted on the lift mast.

The lift mast comprises a first guide 22 that is fixed against vertical reciprocatory movement, a second movable guide 24 mounted by the fixed guide for vertical reciprocity movement, a load carrier 26 mounted to the movable guide for vertical reciprocatory movement and adapted to be horizontally slewed, means 28 for effecting vertical reciprocatory movement of the movable guide and the load carrier, and means 30 for effecting horizontal slewing of the load carrier. The fixed guide is mounted to one end of a horizontal crossbeam 32, which is itself pivotally mounted to the axle housing 34 of the front wheel assembly such that the fixed guide can be pivoted forwardly and rearwardly about a horizontal axis. Means 35 are provided to effect this slight pivotal movement of the fixed guide. The fixed guide is aligned parallel with the longitudinal axis of the lift truck and positioned adjacent to and inward of one of the front wheel sets of the front wheel assembly.

The fixed guide comprises forward and rearward upright legs, 36 and 38, brace members 40 connecting the two legs intermediate the top and bottom thereof, and a base member 42 connecting the bottom ends of the two legs. The forward leg (seen in cross section in FIG. 3) is structurally composed to provide a rearwardly-opening guide channel. The rearward leg (seen in cross section in FIG. 3) is structurally composed to provide a main guide channel opening laterally inward toward the opposite side of the vehicle and a secondary forward-opening guide channel on the back wall of the main channel. The intermediate cross braces are rigidly connected to the outboard sides of the forward and rearward legs. The base member is rigidly connected to the cross beam 32.

The movable guide comprises forward and rearward upright legs, 44 and 46, intermediate brace members 48 connecting the two legs, and a cross head 50 connecting the top ends of the two legs. The forward leg (seen in cross section in FIG. 3) is structurally composed to provide a forward-opening guide channel fitted into the rearward opening guide channel of the forward fixed guide leg 36, and a rearward opening guide channel. The rearward leg (seen in cross section in FIG. 3) is structurally composed to provide a laterally outward opening guide channel fitted into the laterally inward opening guide channel of the rearward guide leg 38, and a laterally inward opening guide channel. Sets of forward and rearward movable-guide leg roller bearings 52, 54 and 55 are provided to vertically guide the movable guide legs as the latter vertically traverse the fixed guide legs. Roller bearings 52 and 54 are journaled to the fixed guide legs and designed to track in the adjacent guide channels of movable guide legs. Roller bearings 55 are journalled to the respective movable guide leg and designed to track in the adjacent guide channel of the fixed guide leg. The forward roller bearings 52 are journalled for rotation on an axis aligned parallel with the longitudinal axis of the vehicle. The rearward roller bearings 54 are journalled for rotation on an axis aligned laterally perpendicular to the longitudinal axis of the vehicle, and the rearward roller bearings 55 are journaled for rotation on an axis aligned parallel with the longitudinal axis of the vehicle.

The load carrier 26 is mounted to the movable guide by a carriage 56 that is adapted to track along the movable guide. The carriage comprises a framework 58 and a load carrier pivot mount 60. The box framework 58 is provided with roller bearings 62 journalled to the forward end section of the framework and designed to track in the adjacent rearward opening guide channel of the movable guide forward leg, and with roller bearings 64 journalled to the rearward end section of the framework and designed to track in the adjacent inwardly opening guide channel of the movable guide rearward leg. The forward roller bearings are journalled for rotation on an axis aligned parallel with the vehicle, and the rearward roller bearings are journalled for rotation on an axis aligned laterally perpendicular to the longitudinal axis of the vehicle. The load carrier pivot mount is rigidly connected to the forward end section of the framework and extends forwardly therefrom, and is provided with pivot journal mounting openings 66 top and bottom at the forward end thereof and with an opening 68 through the center thereof.

As can be seen from FIG. 3, the forward and rearward legs of the fixed and movable guides are laterally offset with the rearward legs being slightly outboard of the forward legs. Consequently, the forward and rearward end sections of the framework are also laterally offset from one another and are connected by askew top and bottom sections of the framework.

The load carrier 26 comprises a carrier frame 70 and a pair of lift forks 72. The carrier frame comprises a peripheral box beam framework with intermediate vertical box beam braces. The frame is pivotally mounted to the forward end section of the load carrier pivot mount 60 by means such as a journal shaft 74. The lift forks are generally L-shaped members, the upper ends of which are pivotally suspended by cross rods 76 mounted by the carrier frame. The lift forks may be positioned along their respective cross rods to vary the spacing between them. The lift forks extend below the carrier frame a sufficient distance to contact the driving surface when the carriage and the carrier frame mounted thereto have been lowered to their lowest levels.

The means 28 for effecting vertical reciprocatory movement of the movable guide and load carrier comprises a telescoping hydraulic ram 78. The base of the ram cylinder is mounted to the base member of the fixed guide. The upper end of the ram rod mounts a sheave encased in .a load bearing bracket 80, the bracket being connected to the cross head of the movable guide. A chain 82 is reeved over the sheave and is attached at one end to the upper end of the ram cylinder and at the other end to the carriage. Thus, when the ram rod is extended the bracket will lift the movable guide in a 1:1 ratio and the chain will lift the carriage in a 2:1 ratio.

The means 30 for horizontally slewing the carrier comprises a cylinder and rod assembly, one end of which is pivotally mounted to the carriage and the other end of which is pivotally mounted to the carrier frame. The cylinder conveniently extends through the opening 68 of the pivot mount. The cylinder and rod assembly has a sufficient stroke to slew the carrier through an angle of from a forward facing position to a laterally facing position.

The means 35 for effecting pivotal movement of the lift mast about the pivot points on the front axle housing comprises a hydraulic cylinder and rod assembly, one end of which is pivotally mounted to the body and the opposite end of which is pivotally mounted to one of the intermediate brace members 40. The cylinder rod assembly has a sufficient stroke to provide the lift mast with the required degree of forward and rearward tilt, which will usually be under 10.

In the operation of the lift truck of the invention, a load such as lumber or the like can be engaged when in the FIG. 1-2 position by driving the lift forks underneath the load. The ram is then actuated to raise the movable guide and the carriage to elevate the carrier sufficiently high to clear the cab. The cylinder rod assembly 30 then retracts to slew the loaded carrier to its laterally facing position shown in dotted lines in FIGS. l-2. The ram may then be retracted to lower the caboverlaying lift fork into the cut-out roof section such that the load will be lowered onto and supported by the cab roof structure.

When the load is engaged by the forward facing load carrier, the bending forces imposed on the carriage are largely transferred to the lift mast guides by the rearward roller bearing sets 54 and 64. When the load carrier is slewed to its laterally facing position, bending moment forces, imposed on the carriage are largely transferred to the lift mast guides by the forward roller bearing sets 52 and 62. During the horizontal slewing of the load carrier, both of the above-mentioned forward and rearward roller bearing sets experience bending moment force.

In the event that it is desired to stabilize the load by clamping down on it when it is positioned as shown in dotted line in FIG. 2, a hydraulic clamp arm assembly 82 is mounted along one side of the body and generally in line with and rearward of the lift mast fixed guide. This assembly comprises an upright arm casing in which a generally L-shaped clamp arm is telescopically positioned, the clamping section of the arm being extended laterally toward the opposite side of the body.

To minimize overloading the load carrier pivot mount, a triangular bumper plate 33 is vertically positioned at the left end of thecross beam 32. The vertical forward edge of the bumper plate contacts the back of the load carrier frame when the latter is being loaded. Appropriate contact members may be located on the back of the frame for contact by the plate 33.

It is believed that the invention will have been clearly understood from the foregoing detailed description of my now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A front loading fork-lift truck comprising a body; forward and rearward wheel assemblies on which said body is carried; an operators station located within the lateral confines of said wheel assemblies; a load bearable support connected to the body and extending upwardly over said operators station, said load bearable support having side and front openings for providing the operator with lateral and forward visibility from beneath the load; load carrier means at the forward end of said lift truck adapted to engage and carry a load; lift means mounted by said body adjacent one side thereof; mounting means interconnecting said lift means and said load carrier means for slewing said load carrier means relative to said lift means about a vertical axis offset from the center of said load carrier means toward said one side from a forward facing position generally central of said body to a laterally-facing position to position the load rearwardly on the load bearable support, said lift means being operable to raise said mounting means for liftingthe load above said load bearable support and to lower said mounting means for lowering said load onto said load bearable support.

2. The fork-lift truck of claim 1, wherein said lift means includes first guide means mounted by said body generally parallel with the longitudinal axis of said forklift truck and fixed against y rtical reciprocatory movement, movable second gui e means mounted by said first guide means for vertical reciprocatory movement and said mounting means interconnecting said load carrier means and said lift means including carriage means mounted by said movable guide means for vertical reciprocatory movement.

3. The lift truck of claim 2 wherein first and second sets of roller bearing assemblies are journalled to one of said guide means to track in guide channels provided in the other guide means and wherein one of such assemblies is arranged. to maintain the relative positions of said guide means when said load carrier means is in said forward facing position and wherein the other of such assemblies is arranged to maintain the relative positions of said guide means when said load carrier means is in said laterally facing position.

4. The fork-lift truck of claim 2 wherein said first guide means is pivotally mounted for slight pivotal movement forwardly and rearwardly about a horizontal pivot axis, and including means for effecting such forward and rearward movement.

5. The fork-lift truck of claim 4 wherein said front wheel assembly includes a front axle housing; and wherein said lift mast includes a lateral beam pivotally mounted to and forwardly of said front axle housing and fixedly mounting said first guide means extending rearwardly of said lateral beam.

6. The fork-lift truck of claim 1, including clamp means adapted to stabilize a load carried by said load bearable support. 

1. A front loading fork-lift truck comprising a body; forward and rearward wheel assemblies on which said body is carried; an operator''s station located within the lateral confines of said wheel assemblies; a load bearable support connected to the body and extending upwardly over said operator''s station, said load bearable support having side and front openings for providing the operator with lateral and forward visibility from beneath the load; load carrier means at the forward end of said lift truck adapted to engage and carry a load; lift means mounted by said body adjacent one side thereof; mounting means interconnecting said lift means and said load carrier means for slewing said load carrier means relative to said lift means about a vertical axis offset from the center of said load carrier means toward said one side from a forward facing position generally central of said body to a laterally-facing position to position the load rearwardly on the load bearable support, said lift means being operable to raise said mounting means for lifting the load above said load bearable support and to lower said mounting means for lowering said load onto said load bearable support.
 2. The fork-lift truck of claim 1, wherein said lift means includes first guide means mounted by said body generally parallel with the longitudinal axis of said fork-lift truck and fixed against vertical reciprocatory movement, movable second guide means mounted by said first guide means for vertical reciprocatory movement and said mounting means interconnecting said load carrier means and said lift means including carriage means mounted by said movable guide means for vertical reciprocatory movement.
 3. The lift truck of claim 2 wherein first and second sets of roller bearing assemblies are journalled to one of said guide means to track in guide channels provided in the other guide means and wherein one of such assemblies is arranged to maintain the relative positions of said guide means when said load carrier means is in said forward facing position and wherein the other of such assemblies is arranged to maintain the relative positions of said guide means when said load carrier means is in said laterally facing position.
 4. The fork-lift truck of claim 2 wherein said first guide means is pivotally mounted for slight pivotal movement forwardly and rearwardly about a horizontal pivot axis, and including means for effecting such forward and rearward movement.
 5. The fork-lift truck of claim 4 wherein said front wheel assembly includes a front axle housing; and wherein said lift mast includes a lateral beam pivotally mounted to and forwardly of said front axle housing and fixedly mounting said first guide means extending rearwardly of said lateral beam.
 6. The fork-lift truck of claim 1, including clamp means adapted to stabilize a load carried by said load bearable support. 